============================================ WARNING: possible recursive locking detected 6.1.27-syzkaller #0 Not tainted -------------------------------------------- syz-executor.4/17943 is trying to acquire lock: ffff00011e736458 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff00011e736458 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4300 [inline] ffff00011e736458 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 but task is already holding lock: ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4300 [inline] ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by syz-executor.4/17943: #0: ffff800015764b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #1: ffff800015764bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #2: ffff800015764bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #3: ffff00011d38c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #3: ffff00011d38c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #3: ffff00011d38c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3807 [inline] #3: ffff00011d38c258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x3878 net/core/dev.c:4225 #4: ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4300 [inline] #4: ffff0000c8ad8cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 #5: ffff0000d61007f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #5: ffff0000d61007f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0xec/0x19c net/ipv6/icmp.c:108 #6: ffff800015764b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #7: ffff800015764bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #8: ffff800015764b60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #9: ffff800015764bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #10: ffff800015764bc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #11: ffff0000d31fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #11: ffff0000d31fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #11: ffff0000d31fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3807 [inline] #11: ffff0000d31fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x3878 net/core/dev.c:4225 stack backtrace: CPU: 1 PID: 17943 Comm: syz-executor.4 Not tainted 6.1.27-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 __lock_acquire+0x6310/0x764c kernel/locking/lockdep.c:5056 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5669 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x54/0x6c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:350 [inline] __netif_tx_lock include/linux/netdevice.h:4300 [inline] sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3820 [inline] __dev_queue_xmit+0x1658/0x3878 net/core/dev.c:4225 dev_queue_xmit include/linux/netdevice.h:3017 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1583 neigh_output include/net/neighbour.h:546 [inline] ip6_finish_output2+0xdb4/0x1a98 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] ip6_finish_output+0x538/0x8c8 net/ipv6/ip6_output.c:206 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:227 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xc30/0x1790 net/ipv6/ndisc.c:508 ndisc_solicit+0x3ac/0x590 neigh_probe+0xc4/0x128 net/core/neighbour.c:1095 __neigh_event_send+0xe50/0x1668 net/core/neighbour.c:1262 neigh_event_send_probe include/net/neighbour.h:470 [inline] neigh_event_send include/net/neighbour.h:476 [inline] neigh_resolve_output+0x17c/0x618 net/core/neighbour.c:1567 neigh_output include/net/neighbour.h:546 [inline] ip6_finish_output2+0xdb4/0x1a98 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] ip6_finish_output+0x538/0x8c8 net/ipv6/ip6_output.c:206 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:227 dst_output include/net/dst.h:444 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1989 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:2009 icmpv6_push_pending_frames+0x288/0x3f4 net/ipv6/icmp.c:303 icmp6_send+0x1194/0x1b08 net/ipv6/icmp.c:619 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2786 dst_link_failure+0x11c/0x160 include/net/dst.h:423 ip_tunnel_xmit+0x1e14/0x28e8 net/ipv4/ip_tunnel.c:819 __gre_xmit net/ipv4/ip_gre.c:469 [inline] erspan_xmit+0x9c8/0x1498 net/ipv4/ip_gre.c:715 __netdev_start_xmit include/linux/netdevice.h:4849 [inline] netdev_start_xmit include/linux/netdevice.h:4863 [inline] xmit_one net/core/dev.c:3593 [inline] dev_hard_start_xmit+0x25c/0x9a4 net/core/dev.c:3609 sch_direct_xmit+0x234/0x548 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3820 [inline] __dev_queue_xmit+0x1658/0x3878 net/core/dev.c:4225 dev_queue_xmit include/linux/netdevice.h:3017 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1583 neigh_output include/net/neighbour.h:546 [inline] ip6_finish_output2+0xdb4/0x1a98 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] ip6_finish_output+0x538/0x8c8 net/ipv6/ip6_output.c:206 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:227 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] rawv6_send_hdrinc+0xd74/0x1bfc net/ipv6/raw.c:655 rawv6_sendmsg+0x10fc/0x1ba8 net/ipv6/raw.c:912 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:828 sock_sendmsg_nosec net/socket.c:716 [inline] sock_sendmsg net/socket.c:736 [inline] __sys_sendto+0x3b4/0x504 net/socket.c:2117 __do_sys_sendto net/socket.c:2129 [inline] __se_sys_sendto net/socket.c:2125 [inline] __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2125 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581